Dry rot

Fusarium solani, Fusarium sulphureum,
Fusarium avenaceum and Fusarium oxysporum

Symptoms

• Small brown spots that turn into dry rot
• Concentric wrinkles on the skin when infection is spreading
• Formation of cavity and mummified tubers
• Usually a mixture of Fusarium and Phoma species
• After planting, dry rot results in poor emergence of the crop or wilting. Dry rot often turns into wet rot (bacteria)

Symptoms: Fusarium solani var. coeruleum

• Light coloured rot that gradually moves into healthy tissue (no sharp outline)
• Dirty white to blue fungal growth in cavities

Symptoms: Fusarium sulphureum

• More aggressive and develops into a “wetter” dry rot
• Clearly outlined dark coloured rot, irregular shape
• Reddish mycelium in cavities

The following species can also cause dry rot:

• Fusarium oxysporum
• Fusarium avenaceum

Infection and spread

• Via seed tubers
• Some Fusarium species are naturally found in the soil
• Via tuber damage (harvesting, processing, chitting, diseases and pests)
• Temperatures between 15 and 20^oC and high relative humidity

Possible confusion with

• Gangrene (Phoma spp.)